i need information about that animal stomach. Are we allowed to eat foods such as (stomach) or the brain or testicle’s of a Goat/Sheep?
In principle, the parts of a halal animal that is properly slaughtered are all permissible, except for its blood which pours out during the slaughtering.
... قل لا أجد في ما أوحي إلي محرما على طاعم يطعمه إلا أن يكون ميتة أو دما مسفوحا
Say, I do not find within that which was revealed to me [anything] forbidden to one who would eat it unless it be a dead animal or blood spilled out ...
Some parts are considered makruh by some scholars, including the Hanafis, because they are perceived to be filthy:
ويحل لهم الطيبات ويحرم عليهم الخبائث
makes lawful for them good things, and makes unlawful for them impure things
كره رسول الله صلى الله عليه وسلم من الشاة الذكر والأنثيين والقبل والغدة والمرارة والمثانة والدم
The Messenger of Allah ﷺ disliked these parts of a goat: the male private part, testicles, the female private part, nodules, gall-bladder, urinary bladder and blood
Stomach is not explicitly mentioned in these, although some consider it makruh as well by analogy with the bladder.